Netfilter - History

History

The netfilter/iptables project was started in 1998 by Rusty Russell, also author of the project's predecessor, ipchains. As the project grew, he founded the Netfilter Core Team (or simply coreteam) in 1999. The software they produce (called netfilter hereafter) is licensed under the GNU General Public License (GPL), and was merged into Linux 2.3 in March 2000. In August 2003, Harald Welte was made chairman of the coreteam, and in April 2004, following a crack-down by the project on those distributing the project's software embedded in routers without complying with the GPL, Welte was granted a historic injunction by a German court against Sitecom Germany, who refused to follow the GPL's terms (see GPL-related disputes). In September 2007, Patrick McHardy, who led development for past years, was elected the new chairman of the coreteam.

Prior to iptables, the predominant software packages for creating Linux firewalls were ipchains in Linux 2.2 and ipfwadm in Linux 2.0, which in turn was based on BSD's ipfw. Both ipchains and ipfwadm alter the networking code so they could manipulate packets, as there was no general packet-control framework until Netfilter.

Whereas ipchains and ipfwadm combine packet filtering and NAT (particularly three specific kinds of NAT, called masquerading, port forwarding and redirection), Netfilter separates packet operations into multiple parts, described below. Each connects to the Netfilter hooks at different points to access packets. The connection tracking and NAT subsystems are more general and more powerful than the stunted versions within ipchains and ipfwadm.